Systems and Methods for Determining Reactivity Indices for Carbon Dioxide Sequestration

This disclosure generally relates to systems and methods for characterizing geological formations. More particularly, the disclosure relates to a system and method for collecting, preparing, and analyzing data relating to the characteristics of one or more geological formations and determining a preferred geological formation for injecting carbon dioxide into.

The concentration of gaseous carbon dioxide (CO) in atmospheres is naturally regulated by planetary geological processes forming a global carbon cycle. However, COis a known greenhouse gas that contributes to radiative forcing of the Earth's atmosphere. Indeed, anthropogenic activities within the past century have contributed to COlevels in the Earth's atmosphere that exceed the levels that the natural global carbon cycle can remove from the atmosphere. Thus, the increasing concentration of COin the Earth's atmosphere is recognized as a concern for the state of the Earth's current climate. Accordingly, various methods have been suggested to abate the increase of COin the Earth's atmosphere or the resulting radiative forcing.

Some conventional methods for decreasing the amount of COreleased to the Earth's atmosphere include carbon capture and storage (e.g., CCS), which is the capture, transport, compression, and sequestration of COinto porous and permeable underground geological rock formations. Non-limiting examples of geological formations that can be used for CO2 sequestration include sedimentary sandstones (e.g., arenite, sub-arkose, arkose), sedimentary carbonates (e.g., limestone, dolostone), sedimentary siltstones and mudstones (e.g., shale), and mafic and ultramafic igneous formations (e.g., basalt, peridotite).

COcan be captured from a point source of an atmospheric emission (e.g., an industrial facility) and/or directly from the atmosphere (e.g., direct air capture). Storage, or sequestration, of COincludes the injection of the COinto a suitable underground geological formation via a borehole drilled into the geological formation.

There is a need for improved systems and methods for analyzing and determining the type and extent of one or more chemical reactions that occur in a geological formation in response to the injection of CO.

For example, provided herein is a method for determining the reactivity of one or more minerals present within a geological formation within a target zone in response to the injection of COinto the target zone, the method comprising: (1) determining one or more mineral and fluid characteristics of the geological formation comprising one or more minerals; and (2) using a reaction rate model to characterize a chemical reactivity of one or more minerals present in the target zone of the geological formation in response to injection of COinto the target zone.

Also provided herein is a method for determining the reactivity of one or more minerals present within a geological formation within a target zone in response to the injection of COinto the target zone, the method comprising: (1) determining one or more mineral and fluid characteristics of the geological formation comprising one or more minerals; (2) using a reaction rate model to characterize the chemical reactivity of one or more minerals present in the target zone of the geological formation in response to injection of COinto the target zone; (3) using a reactivity index model to estimate an amount of one or more minerals in the target zone that would be modified between a first time point and a second point during a COinjection and sequestration operation; and (4) injecting an amount of COinto the target zone based on the chemical reactivity of the one or more minerals present in the target zone.

Other objects and features will be in part apparent and in part pointed out hereinafter.

Provided herein are systems and methods for analyzing and determining the type and extent of one or more chemical reactions that occur in a geological formation in response to the injection of CO.

For example, provided herein is a system for collecting and determining at least one geological formation input relating to geophysical and geochemical properties of the geological formation. Further provided herein is a method of analyzing the at least one geological formation input based on thermophysical and thermodynamic principles to determine a value or metric representing the reactivity of a geological formation to chemical disequilibria created by the injection of COinto the geological formation.

The suitability of a geological formation for sequestering COcan depend on various physical factors of the geological formation. One example of a physical factor is the geological formation's injectivity, which refers to the rate at which COcan be injected into the geological formation without damaging the geological formation. Another example of a physical factor is the geological formation's capacity, which refers to the total effective pore volume of the formation and the mass of COthat may be stored within the geological formation. Yet another example of a physical factor is the geological formation's security or containment, which refers to the likelihood that the injected COwill remain within the geological formation and not otherwise escape to another location, such as another geological formation or the Earth's atmosphere.

The physical state of the injected COmay be in a subcritical gas or liquid phase, a supercritical state, or as an aqueous solute. For example, Formula 1 illustrates an equilibrium between COin its gaseous and aqueous phases.

COis relatively chemically unreactive in the gas phase (g) but chemically reactive in the aqueous phase (aq). Thus, COdissolved in water can dissociate into various inorganic carbonate species. Accordingly, Formula 2 and Formula 3 illustrate the dissociation of aqueous CO.

The species HCO(aq) in Formula 2 is generally negligible with respect to the abundance of other inorganic carbon species. Accordingly, in Formula 2, HCO(aq) is represented as an intermediary between CO(aq) and HCO. Further, as demonstrated in Formula 2 and Formula 3, the acidic compound (H) drives various chemical reactions among gaseous, aqueous, and solid phases of compounds present in geological formations.

For example, Formula 4 demonstrates how acidity in the form of Hcan promote the dissolution of the feldspar mineral oligoclase. For simplicity, Formula 4 is expressed with the reaction products Na, Ca, and Alexisting as aqueous-free ions. However, Na, Ca, and Alcan equally exist as aqueous complexes, depending on the overall chemical system.

Further, bicarbonate (HCO) and carbonate (CO) species can react with aqueous cations to form aqueous carbonate complexes as well as solid carbonate compounds.

In one example, Formula 5 demonstrates how a divalent cation (M) reacts with bicarbonate to form an aqueous carbonate complex. Mcan be Ca, Mg, or Fe.

In another example, Formula 6 demonstrates how a divalent cation (M) reacts with bicarbonate to form a solid carbonate complex. Mcan be Ca, Mg, or Fe.

In yet another example, Formula 7 demonstrates how a divalent cation (M) reacts with carbonate to form a solid carbonate compound. Mcan be Ca, Mg, or Fe.

Thus, it can be determined that the injection of COinto subterranean geological formations can disturb the chemical state within that geological formation. Accordingly, the injection of COinto a geological formation can lead to gas-liquid-solid reactions that can affect the long-term injectivity, capacity, and containment of CO2 sequestered in that geological formation.

Mineral dissolution caused by the injection of COinto a geological formation can be beneficial to CCS field operations. In some examples, mineral dissolution is beneficial because mineral dissolution can increase the porosity of the geological formation by increasing the capacity of the geological formation. In another example, mineral dissolution can be beneficial to CCS field operations because mineral dissolution can increase the permeability of the geological formation by increasing the injectivity of the geological formation.

However, in other instances, mineral dissolution caused by the injection of COinto a geological formation can be detrimental to CCS field operations. In some examples, mineral dissolution is detrimental to CCS field operations because mineral dissolution can increase the likelihood of COleakage from the geological formation by reducing the containment of the geological formation.

Further, mineral precipitation caused by the injection of COinto a geological formation can be beneficial to CCS field operations. In some examples, mineral precipitation is beneficial because mineral precipitation can decrease the likelihood of COleakage through adjacent geological formations by increasing the porosity of the geological formation where the COwas injected into.

Conversely, mineral precipitation caused by the injection of COinto a geological formation can be detrimental to CCS field operations. In some examples, mineral precipitation is detrimental because mineral precipitation can decrease the geological formation's porosity and permeability which can decrease the geological formation's ability to store CO.

Moreover, the thermophysical, geophysical, and geochemical properties of a geological formation can be influenced by the type and abundance of minerals in the geological formation. Thus, the amount of solid minerals in geological formation caused by mineral dissolution and/or mineral precipitation due to CO2 injection can impact the injectivity and capacity of the geological formation.

Further, the amount of solid minerals in the geological formation can dynamically change during a CCS operation. Therefore, it is advantageous to predict, anticipate, or quantify the type and extent of certain chemical reactions that can change the solid mineral content in a geological formation so that the usefulness of the geological formation for CCS can be assessed.

When drilling through a geological formation or other formations for oil, natural gas, or other materials, it is beneficial to determine or estimate the type of geological formation that is being drilled through because the geological formation type can be used to estimate the geological formation's porosity, water saturation, net hydrocarbon content, and permeability and production rates. The geological formation type can also be useful in making drilling decisions based on the estimated mechanical properties of the geological formation.

The geological formation type can be defined by one or more thermophysical, geophysical, and geochemical properties of the geological formation. Thus, provided herein are systems and methods for collecting and determining at least one geological formation input relating to a geological formation's thermophysical, geophysical, and geochemical properties.

Non-limiting examples of geological formation inputs include a mineral make-up, one or more mineral concentrations (e.g., mole fraction, mass fraction, or volume fraction), a mineral surface area, a pore volume, a pore surface area, a pore-size distribution, an electromagnetic resistivity, one or more dielectric properties, imaging data, and acoustic properties of the geological formation, and a composition of the CCS injection fluid.

The mineralogical assemblage in the geological formation (e.g., the mineral make-up of the geological formation) can be determined from well-log interpretation models described herein using data acquired from one or more borehole logging measurements performed within a borehole traversing the geological formation.

Non-limiting examples of rock-forming minerals for sedimentary geological formations (e.g., sedimentary sandstones, sedimentary carbonates, and sedimentary siltstones and mudstones) include quartz, potassium feldspar, plagioclase feldspar, calcite, dolomite, ankerite, siderite, anhydrite, pyrite, illite-clay, smectite-clay, kaolinite-clay, chlorite-clay, and mica.

Non-limiting examples of rock-forming minerals for igneous geological formations (e.g., mafic and ultramafic igneous formations) include olivine (i.e., forsterite-fayalite solid solution), orthopyroxene (i.e., enstatite-ferrosilite solid solution), clinopyroxene (e.g., diopside, augite, pigeonite).

Non-limiting examples of rock-forming minerals for metamorphic geological formations include sillimanite, kyanite, staurolite, andalusite, and garnet.

In some examples, the well-log interpretation model for determining the mineralogical assemblage of the geological formation can include a maximum likelihood model using a resistivity value, a porosity value, a natural gamma ray value, an electromagnetic propagation value, a thermal-neutron decay rate, a spontaneous potential value, and/or a logging combination value. See, Mayer, C., and A. Sibbit. “Global, A New Approach to Computer-Processed Log Interpretation.” Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, September 1980. doi: https://doi.org/10.2118/9341-MS.

In some examples, the well-log interpretation model for determining the mineralogical assemblage of the geological formation can include an elements-to-minerals model using geochemical spectroscopy logs. See, Herron, Michael & Herron, Susan. (1998). Quantitative lithology: Open and cased hole application derived from integrated core chemistry and mineralogy database. Geological Special Society, London, Publications. 136. 81-95. 10.1144/GSL.SP.1998.136.01.08. See also, Craddock, Paul R., Srivastava, Prakhar, Datir, Harish, Rose, David, Zhou, Tong, Mosse, Laurent, and Lalitha Venkataramanan. “Enhanced Mineral Quantification and Uncertainty Analysis from Downhole Spectroscopy Logs Using Variational Autoencoders.” Petrophysics 62 (2021): 614-629. doi: https://doi.org/10.30632/PJV62N6-2021a2.

In another example, a mass-fraction abundance of each mineral in the geological formation can be determined from laboratory measurements.

In one example, the laboratory measurements can be obtained using X-ray diffraction.

In another example, the laboratory measurements can be obtained using infrared spectroscopy techniques. See, Paul R. Craddock, Michael M. Herron Susan L. Herron; “Comparison of Quantitative Mineral Analysis by X-Ray Diffraction and Fourier Transform Infrared Spectroscopy,” Journal of Sedimentary Research 2017; 87 (6): 630-652. doi: https://doi.org/10.2110/jsr.2017.34

The geological formation porosity can be inferred from various petrophysical well logs. Non-limiting examples of well logs include a bulk density log, a neutron porosity log, and a nuclear magnetic resonance log.

Pore-size distribution and/or pore surface area can be inferred from nuclear magnetic resonance measurements or from combined knowledge of the geological formation's mineral concentrations, mineral surface areas, and porosity.

Chemical compositions of the CCS fluid can be measured using spectroscopy techniques. Non-limiting examples of spectroscopy techniques include MS, AAS, and AES. In some examples, the spectroscopy data is analyzed in combination with fluid properties determinable from downhole well logs, formation sampling, and sample testing measurements.

The at least one geological formation input described herein can be determined from a geological formation sample.

Non-limiting examples of the geological formation sample include a rock chip, a rock core, a rock drill cutting, a rock outcrop, a sample from a rock formation surrounding a borehole, and combinations thereof.

In some examples, the geological formation sample is analyzed during or after the formation of a borehole. In some examples, the geological formation sample is analyzed along a depth of the borehole. A non-limiting example of a method for analyzing the geological formation sample via the borehole includes a logging while drilling (e.g., LWD) method. LWD is the measurement of the geological formation properties (e.g., geological formation inputs) during the excavation of the borehole or shortly thereafter through the use of tools and/or sensors integrated into a bottomhole assembly. Another non-limiting example of a method for analyzing the geological formation sample via the borehole includes a wireline logging (e.g., WL) method, in which an instrument, including tools and/or sensors for analyzing the geological formation, is lowered into the borehole after the borehole has been drilled.